Electronic up-conversions of a scene using a pixelated detector array

CROSS-REFERENCE TO RELATED APPLICATIONS

0001The present application claims priority to U.S. Provisional Patent Application Ser. No. 62/603,623, filed Jun. 7, 2017, entitled “ELECTRONIC UP-CONVERSIONS OF A SCENE USING A PIXELATED DETECTOR ARRAY,” the disclosure of which is expressly incorporated by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

0002The invention described herein was made in the performance of official duties by employees of the Department of the Navy and may be manufactured, used and licensed by or for the United States Government for any governmental purpose without payment of any royalties thereon. This invention (Navy Case 200,440) is assigned to the United States Government and is available for licensing for commercial purposes. Licensing and technical inquiries may be directed to the Technology Transfer Office, Naval Surface Warfare Center Crane, email: Cran_CTO@navy.mil.

FIELD OF THE INVENTION

0003The present invention relates to a system for viewing infrared light by up-converting with a pixelated detector array.

Background and Summary of the Invention

0004The present invention relates to an up-conversion system for allowing infrared (IR) light, including short wave infrared (SWIR) light), to be viewed by a night vision goggle (NVG) system. Typical NVG systems detect and amplify visible light, including near infrared (NIR) light, with a photomultiplier/image intensifier tube to allow an operator to see in low light environments. Under typical nighttime conditions, both SWIR and NIR ambient light are present, with SWIR light exceeding NIR light by more than an order of magnitude. There is a need for an efficient and low cost means of allowing SWIR light to be viewed in a visible spectrum by NVG systems without requiring a large amount of power.

0005According to an illustrative embodiment of the present disclosure, SWIR diodes can generate current when receiving SWIR light. This current can be amplified by transimpedance amplifiers to allow LEDs to emit NIR light with minimal power input.

0006According to a further illustrative embodiment of the present disclosure, an up-conversion system can be placed in a NVG system between an objective lens and a photomultiplier tube. The up-conversion system converts SWIR to NIR light, allowing the photomultiplier tube to amplify the converted NIR light.

0007Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

0008The detailed description of the drawings particularly refers to the accompanying figures in which:

0009<figref idref="DRAWINGS">FIG. 1</figref> shows an exemplary system for converting SWIR to NIR light.

0010<figref idref="DRAWINGS">FIG. 2</figref> shows an exemplary single cell for converting SWIT to NIR light.

0011<figref idref="DRAWINGS">FIG. 3</figref> shows exemplary components of a NVG system.

0012<figref idref="DRAWINGS">FIG. 4</figref> shows an exemplary circuit layout for an up-conversion system.

DETAILED DESCRIPTION OF THE DRAWINGS

0013The embodiments of the invention described herein are not intended to be exhaustive or to limit the invention to precise forms disclosed. Rather, the embodiments selected for description have been chosen to enable one skilled in the art to practice the invention.

0014<figref idref="DRAWINGS">FIG. 1</figref> shows an exemplary up-conversion system <b>1</b>. Up-conversion system <b>1</b> can use a bump or flip chip bonded setup comprising a plurality of SWIR photodiodes <b>11</b>, a plurality of transimpedance amplifiers <b>13</b>, and a plurality of NIR emitters <b>15</b>. SWIR photodiodes <b>11</b> absorb incoming SWIR light to generate an electrical current. The electrical current is amplified by amplifier <b>13</b> to allow NIR emitters (e.g., red LEDs) to emit visible light.

0015<figref idref="DRAWINGS">FIG. 2</figref> shows an exemplary up-conversion system <b>1</b> with a single exemplary SWIR photodiode <b>11</b>, amplifier <b>13</b>, and NIR emitter <b>15</b>. For ideal performance, photodiode <b>11</b> should have a high absorption coefficient in the spectral band of interest (e.g., infrared), epitaxy growth compatibility with a low cost and scalable substrate, and a material system compatible with donor and acceptor dopants to form p-n junctions. Examples of photodiode <b>11</b> include InGaAs, HgCdTe, SiGe superlattices, and GeSn. The final light emission after detection and amplification can be through an array of light emitting diodes (LEDs) that have direct one-to-one signal transfer such that each incident of SWIR light detection creates a single NIR light signal.

0016<figref idref="DRAWINGS">FIG. 3</figref> shows an exemplary NVG system broken down into its core components. An objective lens <b>31</b> is directed towards a target of interest. A housing assembly <b>33</b> covers an image intensifier tube <b>35</b> and connects to the objective lens <b>31</b> and an eyepiece <b>37</b>. An exemplary up-conversion system (not shown) can be placed within housing assembly <b>33</b> between objective lens <b>31</b> and image intensifier tube <b>35</b> such that incoming SWIR light can first enter the objective lens <b>31</b> and then reach up-conversion system. NIR light emitted by the up-conversion system can then reach the image intensifier tube <b>35</b> to amplify the light and allow an operator to view the light through the eyepiece <b>37</b>. Exemplary up-conversion systems can be about 10 mm thick, allowing for insertion into existing NVG systems with zero or minimal modifications to the housing.

0017<figref idref="DRAWINGS">FIG. 4</figref> shows an exemplary circuit of an up-conversion system (e.g., as shown in <figref idref="DRAWINGS">FIG. 2</figref>). Photodiode <b>11</b> creates a current upon receiving SWIR light. Transimpedance amplifier <b>41</b> amplifies the current created by photodiode <b>11</b>. NIR emitter <b>15</b> (e.g., an LED) generates NIR light. Transistor Q<b>1</b><b>43</b> is an n-channel MOSFET, and a power source <b>45</b> of 5V is provided. A 2,000 pixels by 2,000 pixels (4 million total pixels) array of exemplary circuits can operate with a power draw of about 485 mW across all of the amplifiers and about 97 mW across all of the NIR emitters.

0018Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the spirit and scope of the invention as described and defined in the following claims.